全文获取类型
收费全文 | 899篇 |
免费 | 48篇 |
出版年
2023年 | 3篇 |
2022年 | 13篇 |
2021年 | 24篇 |
2020年 | 5篇 |
2019年 | 17篇 |
2018年 | 22篇 |
2017年 | 16篇 |
2016年 | 31篇 |
2015年 | 48篇 |
2014年 | 39篇 |
2013年 | 64篇 |
2012年 | 61篇 |
2011年 | 75篇 |
2010年 | 37篇 |
2009年 | 37篇 |
2008年 | 51篇 |
2007年 | 67篇 |
2006年 | 51篇 |
2005年 | 33篇 |
2004年 | 41篇 |
2003年 | 32篇 |
2002年 | 32篇 |
2001年 | 12篇 |
2000年 | 11篇 |
1999年 | 11篇 |
1998年 | 4篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 7篇 |
1978年 | 7篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1968年 | 3篇 |
排序方式: 共有947条查询结果,搜索用时 46 毫秒
81.
82.
83.
Sensitivity Analysis of Environmental Process Modeling in a Life Cycle Context: A Case Study of Hemp Crop Production
下载免费PDF全文
![点击此处可从《Journal of Industrial Ecology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Andrianandraina Anne Ventura Tristan Senga Kiessé Bogdan Cazacliu Rachida Idir Hayo M. G. van der Werf 《Journal of Industrial Ecology》2015,19(6):978-993
The aim of this article is to develop a methodological approach allowing to assess the influence of parameters of one or more elementary processes in the foreground system, on the outcomes of a life cycle assessment (LCA) study. From this perspective, the method must be able to: (1) include foreground process modeling in order to avoid the assumption of proportionality between inventory data and reference flows; (2) quantify influences of foreground processes’ parameters (and, possibly, interactions between parameters); and (3) identify trends (either increasing or decreasing) for each parameter on each indicator in order to determine the most favorable direction for parametric variation. These objectives can be reached by combining foreground system modeling, a set of two different sensitivity analysis methods (each one providing different and complementary information), and LCA. The proposed method is applied to a case study of hemp‐based insulation materials for buildings. The present study will focus on the agricultural stage as a foreground system and as a first step encompassing the entire life cycle. A set of technological recommendations were identified for hemp farmers in order to reduce the crop's environmental impacts (from –11% to –89% according to the considered impact category). One of the main limitations of the approach is the need for a detailed model of the foreground process. Further, the method is, at present, rather time‐consuming. However, it offers long‐term advantages given that the higher level of model detail adds robustness to the LCA results. 相似文献
84.
Drivers of temporal changes in temperate forest plant diversity vary across spatial scales
下载免费PDF全文
![点击此处可从《Global Change Biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Markus Bernhardt‐Römermann Lander Baeten Dylan Craven Pieter De Frenne Radim Hédl Jonathan Lenoir Didier Bert Jörg Brunet Markéta Chudomelová Guillaume Decocq Hartmut Dierschke Thomas Dirnböck Inken Dörfler Thilo Heinken Martin Hermy Patrick Hommel Bogdan Jaroszewicz Andrzej Keczyński Daniel L. Kelly Keith J. Kirby Martin Kopecký Martin Macek František Máliš Michael Mirtl Fraser J.G. Mitchell Tobias Naaf Miles Newman George Peterken Petr Petřík Wolfgang Schmidt Tibor Standovár Zoltán Tóth Hans Van Calster Gorik Verstraeten Jozef Vladovič Ondřej Vild Monika Wulf Kris Verheyen 《Global Change Biology》2015,21(10):3726-3737
Global biodiversity is affected by numerous environmental drivers. Yet, the extent to which global environmental changes contribute to changes in local diversity is poorly understood. We investigated biodiversity changes in a meta‐analysis of 39 resurvey studies in European temperate forests (3988 vegetation records in total, 17–75 years between the two surveys) by assessing the importance of (i) coarse‐resolution (i.e., among sites) vs. fine‐resolution (i.e., within sites) environmental differences and (ii) changing environmental conditions between surveys. Our results clarify the mechanisms underlying the direction and magnitude of local‐scale biodiversity changes. While not detecting any net local diversity loss, we observed considerable among‐site variation, partly explained by temporal changes in light availability (a local driver) and density of large herbivores (a regional driver). Furthermore, strong evidence was found that presurvey levels of nitrogen deposition determined subsequent diversity changes. We conclude that models forecasting future biodiversity changes should consider coarse‐resolution environmental changes, account for differences in baseline environmental conditions and for local changes in fine‐resolution environmental conditions. 相似文献
85.
86.
Bogdan Alexandru Stoica Gabriela Bordeianu Raluca Stanescu Dragomir N. Serban Mihai Nechifor 《Journal of biological inorganic chemistry》2011,16(5):753-761
Allopurinol is a prodrug converted to oxypurinol by xanthine oxidase, a process followed by an efficient enzyme inhibition.
Using a lucigenin-enhanced chemiluminescence method, we found that, under alkaline conditions, superoxide radicals are produced
in large amounts in the first step of the interaction between the enzyme and the inhibitor. A comparison between lucigenin
and cytochrome c as final detectors revealed that only the chemiluminescence technique is able to detect the superoxide anions from allopurinol
oxidation. The allopurinol–xanthine oxidase–lucigenin system can be used for the quantification of various free-radical scavengers,
in particular superoxide dismutase mimics. Three manganese compounds from different structural classes [manganese(II) chloride,
manganese N,N′-bis(salicylidiene)ethylenediamine chloride, and manganese(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin] were compared at five concentrations (0.01, 0.1, 1, 10, and 100 μM). The method is fast,
16 times more sensitive than the cytochrome c assay at pH 10.1 and could be used for in vivo investigations avoiding the lucigenin redox cycle. If the concentrations of
the reagents are increased and Tween 20 is added, the method is also operative at pH 7.4. 相似文献
87.
Vasylieva N Barnych B Meiller A Maucler C Pollegioni L Lin JS Barbier D Marinesco S 《Biosensors & bioelectronics》2011,26(10):3993-4000
Poly(ethylene glycol) diglycidyl ether (PEGDE) is widely used as an additive for cross-linking polymers bearing amine, hydroxyl, or carboxyl groups. However, the idea of using PEGDE alone for immobilizing proteins on biosensors has never been thoroughly explored. We report the successful fabrication of microelectrode biosensors based on glucose oxidase, d-amino acid oxidase, and glutamate oxidase immobilized using PEGDE. We found that biosensors made with PEGDE exhibited high sensitivity and a response time on the order of seconds, which is sufficient for observing biological processes in vivo. The enzymatic activity on these biosensors was highly stable over several months when they were stored at 4 °C, and over at least 3d at 37 °C. Glucose microelectrode biosensors implanted in the central nervous system of anesthetized rats reliably monitored changes in brain glucose levels induced by sequential administration of insulin and glucose. PEGDE provides a simple, low cost, non-toxic alternative for the preparation of in vivo microelectrode biosensors. 相似文献
88.
Wu SC Yoon D Chin J van Kirk K Seethala R Golla R He B Harrity T Kunselman LK Morgan NN Ponticiello RP Taylor JR Zebo R Harper TW Li W Wang M Zhang L Sleczka BG Nayeem A Sheriff S Camac DM Morin PE Everlof JG Li YX Ferraro CA Kieltyka K Shou W Vath MB Zvyaga TA Gordon DA Robl JA 《Bioorganic & medicinal chemistry letters》2011,21(22):6693-6698
Derived from the HTS hit 1, a series of hydroxyisoquinolines was discovered as potent and selective 11β-HSD1 inhibitors with good cross species activity. Optimization of substituents at the 1 and 4 positions of the isoquinoline group in addition to the core modifications, with a special focus on enhancing metabolic stability and aqueous solubility, resulted in the identification of several compounds as potent advanced leads. 相似文献
89.
Bridget J. M. Stutchbury Elizabeth A. Gow Tyler Done Maggie MacPherson James W. Fox Vsevolod Afanasyev 《Proceedings. Biological sciences / The Royal Society》2011,278(1702):131-137
Each autumn billions of songbirds migrate between the temperate zone and tropics, but little is known about how events on the breeding grounds affect migration to the tropics. Here, we use light level geolocators to track the autumn migration of wood thrushes Hylocichla mustelina and test for the first time if late moult and poor physiological condition prior to migration delays arrival on the winter territory. Late nesting thrushes postponed feather moult, and birds with less advanced moult in August were significantly farther north on 10 October while en route to the tropics. Individuals in relatively poor energetic condition in August (high β-Hydroxybutyrate, low triglyceride, narrow feather growth bars) passed into the tropics significantly later in October. However, late moult and poor pre-migratory condition did not result in late arrival on the winter territory because stopover duration was highly variable late in migration. Although carry-over effects from the winter territory to spring migration may be strong in migratory songbirds, our study suggests that high reproductive effort late in the season does not impose time constraints that delay winter territory acquisition. 相似文献
90.
Lucyna Firlej Bogdan Kuchta Michael W. Roth Carlos Wexler 《Journal of molecular modeling》2011,17(4):811-816
The interplay between the torsional potential energy and the scaling of the 1-4 van der Waals and Coulomb interactions determines
the stiffness of flexible molecules. In this paper we demonstrate for the first time that the precise value of the nonbond
scaling factor (SF)—often a value assumed without justification—has a significant effect on the critical properties and mechanisms
of systems undergoing a phase transition, and that, for accurate simulations, this scaling factor is highly dependent on the
system under consideration. In particular, by analyzing the melting of n-alkanes (hexane C6, dodecane C12, tetracosane C24)
on graphite, we show that the SF is not constant over varying alkane chain lengths when the structural correlated transformations
are concerned. Instead, monotonic decrease of SF with the molecular length drives a cross-over between two distinct mechanisms
for melting in such systems. In a broad sense we show that the choice for SF in any simulation containing adsorbed or correlated
long molecules needs to be carefully considered. 相似文献